MIT Architecture
M. Andersen
Introduction to Building Technology
Course 4.401
assigned April 5, 2006 Spring 2006
due April 12, 2006
HOMEWORK #5
Designing with Natural Light – Visual comfort
Questions
a. For a museum, what are the critical issues of using zenithal natural light for a museum ?
and of using artificial light ?
b. What is the least adequate orientation for
this façade equipped with fixed vertical solar
protection devices, if the building is situated
at our latitude?
c. If you were to define the ideal window system on a South oriented façade in Boston for an
office space that is 10 meter deep, what would be your 5 major criteria ? same question
for a North-oriented façade.
Problems
1. The individual reading spaces of the Phillips Exeter Academy Library (Exeter, NH, designed
by Louis Kahn in 1967-1970), are positioned along the periphery of the building, and are
separated from the large central atrium by the rows of book shelves. In addition to the
diffuse light brought in by the large superior windows, each reading cell benefits from
direct sunlight through a small lateral window positioned at desk height and equipped with
a sliding wood blind. All four façades have been treated equally as far as solar protections
are concerned.
Direct sunlight should be avoided on the work space at anytime.
On the plane and section views of individual reading cells given on the next page, determine
the limit angles α1, α2 and β1 for solar penetration and report the angles on a tracing paper
over the given shadow protractor, by shading the areas corresponding to sun directions
for which the lower windows always benefit from total protection.
1/4 Upper and lower windows pointed out on façade
Individual reading cells
Plane view
Axonometric view
Section view
20
30
60
10
10
20
30
40
20
30
40
60
50
70
70
0
50
50
40
10
70
80
80
60
80
90
90
Image by MIT OCW.
Superpose the projected shadows on the stereographical view given on the next page,
which corresponds to the latitude 42°22'N of Exeter for the four façade orientations.
Analyze the solar penetration occurrences over the year for each façade orientation.
What are the critical issues of choosing to have no solar protection for the upper
windows?
What are the critical issues of having sliding wooden blinds for the lower windows as sole
shading system?
2/4 June
21
18
21
g3
1
0
Oct
2400
0
20
0
30
0
40
0
50
0
60
0
70
0
80
0
90
0
30
14
12
0
45
0
60
8
16
255
Se
pt
23
10
10
17
Fe
N ov
0
y 26
0
Au
270
0
0
Ma
0
July
285
0
15
0
75
0
900
M
300
0
Ap
r1
4
315
0
6
330
0
ar
21
345
Jan
27
16
b2
6
1050
Building’s
orientation
1200
Dec 21
2250
1350
2100
1500
1950
165
0
1800
Image by MIT OCW.
2. Consider the window whose section view is given here.
It belongs to a South oriented façade of a building
situated at 48°N.
How would you dimension a fixed horizontal solar
protection in order that at noon solar time, the whole window is in the shadow between May 21 and July 21 (around the summer solstice where solar gains are to be avoided) whereas no shadow should occur between November 21 and January 21 (winter solstice where
solar gains are desired) ? Int.
Ext.
Use the fact that both on January 21 and November 21, the sun’s apparent elevation η is 22.2°, while it is of 62° on May 21 and July 21. Reading assignment from Textbook
“Introduction to Architectural Science” by Szokolay: § 2.2 to 2.4
Additional readings relevant to lecture topics:
Image by MIT OCW.
"How Buildings Work" by Allen: Chap 13
"Heating Cooling Lighting" by Lechner: Chap 9 + Chaps 12-13
3/4 Design project:
Instructions for the next report (Lighting diagnostic portion of it)
Choose a space within your building where the contribution of daylight to the inside illumination
is preponderant. Basically, what your diagnostic should provide is a conclusion on whether the
lighting, and especially daylighting, conditions are acceptable, good, excellent or poor and why.
More specifically, supporting your analysis with pictures and drawings, and, if you think it would
be beneficial, using the manual heliodon presented in class1 (picture below) with a rough model
of the space, summarize and illustrate:
• the moments of the year where sunlight penetration is expected, based on the orientation
of the openings and the masking of the surrounding buildings / natural obstacles,; specify
the portions of the space that will be sunlit
• the types of openings, the types of glazing, the types of shading system and the
performances of their combination as far as glare and contrast prevention as well as heat
gains and losses issues are concerned; always specify the portions of the space where
your analysis is applicable
• what delimits the portions of the space mainly relying on daylighting from those essentially
or only relying on electric lighting and to what extent the scission between the two is
recognizable
• how reflection on inside walls is used to illuminate the space and what kind of surfaces we
have on the floor, side walls, ceiling
Portable Heliodon
1
Coordinate with Jeff Anderson for borrowing it.
4/4